Gestational diabetes

Women can develop diabetes during pregnancy. What are the risks for baby and mother? Can it be prevented?

What is gestational diabetes?

Diabetes that develops during pregnancy is called gestational diabetes. Due to hormonal changes during pregnancy, some mothers-to-be experience an increase in their blood sugar levels. More specifically, the placenta produces hormones that interfere with the effects of insulin (a hormone that controls blood sugar levels).

Gestational diabetes affects between 3 percent and 20 percent of pregnant women in Quebec, depending on the region. It most often appears in the second trimester of pregnancy and usually resolves after childbirth.

Symptoms of gestational diabetes

In general, diabetes does not cause obvious symptoms in pregnancy, as the discomforts it causes are common among mothers-to-be. As a result, the symptoms of gestational diabetes often go unnoticed.

Some women who suffer from gestational diabetes may experience the following symptoms:

• Dizziness or increased fatigue
• Increased thirst
• More frequent need to urinate and greater urine output
• Headaches
• Dry mouth

If you think you may have gestational diabetes, consult a doctor right away.

Risks to the baby at birth

A baby whose mother has gestational diabetes may present with the following at birth:

• Above-average weight (more than 4 kg/9 lb)
• Injury to the upper body when the baby’s shoulders emerge (due to their larger size)
• Hypoglycemia (low blood sugar)
• Jaundice
• Lack of calcium in the blood
• Difficulty breathing

Gestational diabetes does not increase the risk of birth defects or the risk of the child being born with diabetes. However, it does increase their risk of obesity and glucose intolerance in early adulthood.

Risks to the mother

Gestational diabetes may:

• Increase the risk of delivery by caesarean section or lead to a more difficult vaginal delivery, due to the weight of the baby
• Cause preeclampsia (high blood pressure during pregnancy)
• Cause an excess of amniotic fluid, which may trigger a preterm birth
• Increase the long-term risk of developing type 2 diabetes

What are the risk factors?

Women with any of the following risk factors or conditions are more likely to develop gestational diabetes:

• Over 35 years old
• Obesity (BMI over 30)
• Pregnancy weight gain of more than 15 kg (35 lb), regardless of pre-pregnancy weight

• A medical history of gestational diabetes
• Having previously given birth to a baby weighing more than 4 kg (9 lb)
• A family history of diabetes (father, mother, brother, or sister)
• Taking cortisone-based medication on a regular basis
• Polycystic ovary syndrome
• Acanthosis nigricans, a type of skin discolouration
• A history of abnormally high blood sugar levels or glucose intolerance
• Being of Indigenous, Latin American, Asian, Arab, or African descent

Screening test

All women should be tested for gestational diabetes between weeks 24 and 28 of pregnancy. However, women with several risk factors should be screened sooner, at around week 12.

There are two types of screening tests. Your prenatal care provider will tell you which one you’ll need to take. One of the tests is done on an empty stomach, while the other is not. Both involve drinking a sugary solution, then undergoing a blood test to gauge how your body reacts to the sugar.

How can gestational diabetes be prevented?

There are thing you can do to help prevent gestational diabetes:

• Maintain a healthy weight.
• Eat a balanced and varied diet.
• Stay physically active before and during your pregnancy. For example, walking is a great way to start getting more exercise.
• Control your weight gain during pregnancy.
• Return to your pre-pregnancy weight, ideally within one year of giving birth. This will keep you from retaining extra weight from one pregnancy to the next, which increases your risk of developing diabetes in a subsequent pregnancy or type 2 diabetes later on.

What should you do if you have gestational diabetes?

The professional monitoring your pregnancy may recommend that you consult a nutritionist to make changes to your diet (e.g., eating fewer carbohydrates and sugary foods and more healthy, nutritious foods). You should also try to get more physical activity.

If you follow these tips, your blood sugar level should go down. There’s no need to eliminate carbohydrates from your diet completely, but you should aim to spread them out over the course of the day.

In many cases, gestational diabetes can be managed with healthy eating and exercise. However, if this does not work, you may need to start insulin treatment.

How to recognize hypoglycemia

Hypoglycemia occurs when your blood sugar level falls below the normal range for a pregnant woman. Here are the symptoms of hypoglycemia:

• Extreme fatigue
• Abnormal sweating
• Headaches
• Dizziness and weakness
• Trembling

Hypoglycemia may be caused by taking too much medication (insulin) relative to the amount of food you’ve eaten. Over-exercising, drinking alcohol, and skipping meals can also cause hypoglycemia.

Things to keep in mind

• Having a healthy weight before pregnancy reduces the risk of developing gestational diabetes.
• It’s often possible to control gestational diabetes by changing your diet and exercising.
• Uncontrolled gestational diabetes poses risks for both mother and baby.

Scientific review: Dr. Jean-Philippe Blais, family physician specializing in perinatal care Research and writing:The Naître et grandir team Updated: July 2024

Photo: 123rf.com/kzenon